% Florian Sihler, 2022
% Licensed under GNU General Public License version 3
% https://opensource.org/licenses/gpl-3.0.html
\def\filename{fancyqr}
\ProvidesPackage{\filename}[2022/08/19 version v1.1 Fancy QR-Codes]
\RequirePackage{tikz, qrcode}

% element
% x: {\the\j}; y: {\the\i} | \@max@x \@max@y
\def\FancyQrColor#1{\if@fancyqr@gradient
\pgfmathsetmacro\angle{Mod(\fancyqr@gradient@angle+225,360)}% rotate to align 0 to the right
\pgfmathsetmacro\gradient{%
   % we do rotate the x and y points before color drawing by
   % Mod(\fancyqr@gradient@angle,360) with the shifted origin
   % Old: #3/2 #4/2
   ((\the\j-\@max@x/2)*cos(\angle) - (\the\i-\@max@y/2)*sin(\angle) + \@max@x/2)/\@max@x * 50% rel x [0,1]
   + ((\the\j-\@max@x/2)*sin(\angle) + (\the\i-\@max@y/2)*cos(\angle) + \@max@y/2)/\@max@y * 50% rel y [0,1]
   }\@declaredcolor{qr@fancy@gradient@br!\gradient!qr@fancy@gradient@tl}\else\@declaredcolor{qr@fancy@gradient@tl}\fi{#1}}

% O 1 O
% 2 X 3
% O 4 O
% uses \@up\@left\@right\@down
\def\GetPattern{%
\ifcsname qcc\@up\@left\@right\@down\endcsname
   \csname qcc\@up\@left\@right\@down\endcsname
\else\rule\qr@modulesize\z@\fi}

\tikzset{qrrc/.style={rounded corners=.5\qr@modulesize},qrrd/.style={fill}}

% is larger to be compensated by overlaps
\def\qrm{\dimexpr\qr@modulesize+.15\p@\relax}
\long\def\qr@newpattern#1#2#3#4#5{%
\expandafter\def\csname qcc#1#2#3#4\endcsname{%
   \parbox[b][\qr@modulesize]\qr@modulesize{\kern-.075\p@\smash{\clap{\tikz[x=\qrm,y=\qrm,inner sep=\z@,outer sep=\z@]{\path[qrrd]#5;}}}}%
}}

\def\FancyLoadDefault{%
% .
\qr@newpattern0000{[qrrc](0,0)rectangle(\qrm,\qrm)}%
% | | - -
\qr@newpattern1000{(0,\qrm)[qrrc]--(0,0)--(\qrm,0)[sharp corners]--(\qrm,\qrm)--cycle}%
\qr@newpattern0001{(0,0)[qrrc]--(0,\qrm)--(\qrm,\qrm)[sharp corners]--(\qrm,0)--cycle}%
\qr@newpattern0100{(0,0)[qrrc]--(\qrm,0)--(\qrm,\qrm)[sharp corners]--(0,\qrm)--cycle}%
\qr@newpattern0010{(\qrm,0)[qrrc]--(0,0)--(0,\qrm)[sharp corners]--(\qrm,\qrm)--cycle}%
% corners
\qr@newpattern1100{(\qrm,\qrm)[qrrc]--(\qrm,0)[sharp corners]--(0,0)--(0,\qrm)--cycle}% top left
\qr@newpattern1010{(0,\qrm)[qrrc]--(0,0)[sharp corners]--(\qrm,0)--(\qrm,\qrm)--cycle}% top right
\qr@newpattern0101{(0,\qrm)[qrrc]--(\qrm,\qrm)[sharp corners]--(\qrm,0)--(0,0)--cycle}% bottom left
\qr@newpattern0011{(0,0)[qrrc]--(0,\qrm)[sharp corners]--(\qrm,\qrm)--(\qrm,0)--cycle}% bottom right
% straights | --
\qr@newpattern1001{(0,0)rectangle(\qrm,\qrm)}%
\qr@newpattern0110{(0,0)rectangle(\qrm,\qrm)}%
% enclosed
\qr@newpattern1111{(0,0)rectangle(\qrm,\qrm)}%
% t's
\qr@newpattern0111{(0,0)rectangle(\qrm,\qrm)}%
\qr@newpattern1011{(0,0)rectangle(\qrm,\qrm)}%
\qr@newpattern1101{(0,0)rectangle(\qrm,\qrm)}%
\qr@newpattern1110{(0,0)rectangle(\qrm,\qrm)}%
}
\FancyLoadDefault % allows to reset the style after other loads
\def\@fancy@qr@default@name{default}

\def\FancyQrLoad#1{\let\@tmp\newpattern\let\newpattern\qr@newpattern\@bsphack\def\@@tmp{#1}\ifx\@@tmp\@fancy@qr@default@name\FancyLoadDefault\else
\expandafter\edef\csname pingu@lib@#1@atcode\endcsname{\the\catcode`\@}%
\catcode`\@=11\relax
\input{fancyqr-style-#1.code}
\catcode`\@=\csname pingu@lib@#1@atcode\endcsname
\fi\@esphack\let\newpattern\@tmp\let\@tmp\relax}


% modify the getter so everything that is not defined is white:
\def\fancy@qr@matrixentry#1#2#3{%
   \ifcsname #1@#2@#3\endcsname
   % #1 = matrix name
   % #2 = row number
   % #3 = column number
   \csname #1@#2@#3\endcsname
   \else\qr@white@format\fi
}%

\def\FancyQrDoNotPrintSquare#1#2{\def\fancy@qr@donotprint@center@x{#1}\def\fancy@qr@donotprint@center@y{#2}}
\FancyQrDoNotPrintSquare00

\newif\iffancy@qr@do@print@
\def\qr@fancy@updateif#1#2{\fancy@qr@do@print@true
\ifnum#1>\@do@y@min\relax \ifnum#1<\@do@y@max\relax \ifnum#2>\@do@x@min\relax \ifnum#2<\@do@x@max\relax \fancy@qr@do@print@false \fi\fi\fi\fi}

\newif\iffancy@qr@roundcut@
\fancy@qr@roundcut@true
\let\FancyQrHardCut\fancy@qr@roundcut@false
\let\FancyQrRoundCut\fancy@qr@roundcut@true

% clear plus if not to be printed
\def\qr@fancy@clear@surround#1#2#3{%
   \qr@fancy@updateif{\the\numexpr#2-1}{#3}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@\the\numexpr#2-1 @#3\endcsname\@undefined \fi
   \qr@fancy@updateif{\the\numexpr#2+1}{#3}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@\the\numexpr#2+1 @#3\endcsname\@undefined \fi
   \qr@fancy@updateif{#2}{\the\numexpr#3-1}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@#2@\the\numexpr#3-1\endcsname\@undefined \fi
   \qr@fancy@updateif{#2}{\the\numexpr#3+1}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@#2@\the\numexpr#3+1\endcsname\@undefined \fi
}

\newif\if@fancyqr@image@

\def\fancy@qr@printmatrix#1{%
   \def\qr@white{0}\def\qr@black{1}%
   \let\qr@black@fixed\qr@black
   \let\qr@white@fixed\qr@white
   \let\qr@black@format\qr@black
   \let\qr@white@format\qr@white
  %Set module size
  \qr@modulesize=\qr@desiredheight
  \divide\qr@modulesize by \qr@size\relax
  \qr@minipagewidth=\qr@modulesize
  \if@fancyqr@image@% image is in \fancyqr@imgbox
   \pgfmathsetmacro\@x{int(ceil((.5\wd\fancyqr@imgbox)/\qr@modulesize)+\fancyqr@img@padding@x)}%
   \pgfmathsetmacro\@y{int(ceil((.5\ht\fancyqr@imgbox+.5\dp\fancyqr@imgbox)/\qr@modulesize)+\fancyqr@img@padding@y)}%
   \FancyQrDoNotPrintSquare\@x\@y
  \fi
  \multiply\qr@minipagewidth by \qr@size\relax
  \ifqr@tight \else \advance\qr@minipagewidth by 8\qr@modulesize \fi
   \minipage\qr@minipagewidth
      \baselineskip=\qr@modulesize
      \ifqr@tight\else\rule\z@{4\qr@modulesize}\par\fi% %Blank space at top.
      \edef\@max@x{\qr@numberofrowsinmatrix{#1}}%
      \edef\@max@y{\qr@numberofcolsinmatrix{#1}}%
      \edef\@do@x@min{\the\numexpr\@max@x/2-\fancy@qr@donotprint@center@x-1}%
      \edef\@do@x@max{\the\numexpr\@max@x/2+\fancy@qr@donotprint@center@x+1}%
      \edef\@do@y@min{\the\numexpr\@max@y/2-\fancy@qr@donotprint@center@y-1}%
      \edef\@do@y@max{\the\numexpr\@max@y/2+\fancy@qr@donotprint@center@y+1}%
      \qr@for \i=1 to \@max@y by 1{%
      \ifqr@tight\else\rule{4\qr@modulesize}\z@\fi% %Blank space at left.
      \qr@for \j=1 to \@max@x by 1{%
         \qr@fancy@updateif\i\j
         \iffancy@qr@do@print@
         \edef\@mid{\qr@matrixentry{#1}{\the\i}{\the\j}}%
         \ifnum\@mid=\qr@white
            \rule\qr@modulesize\z@
         \else% if not white, get its pattern
            \iffancy@qr@roundcut@\qr@fancy@clear@surround{#1}{\the\i}{\the\j}\fi
            \edef\@up{\qr@matrixentry{#1}{\the\numexpr\the\i-1}{\the\j}}%
            \edef\@left{\qr@matrixentry{#1}{\the\i}{\the\numexpr\the\j-1}}%
            \edef\@right{\qr@matrixentry{#1}{\the\i}{\the\numexpr\the\j+1}}%
            \edef\@down{\qr@matrixentry{#1}{\the\numexpr\the\i+1}{\the\j}}%
            \FancyQrColor{\GetPattern}%
         \fi\else \rule\qr@modulesize\z@\fi
      }\par}%
      \ifqr@tight\else\rule\z@{4\qr@modulesize}\par\fi
   \endminipage
   \if@fancyqr@image@\nobreak
   \llap{\parbox\qr@minipagewidth{\centering\usebox\fancyqr@imgbox}}\fi
}%

\def\fancy@qr@setup#1{%
   \qr@creatematrix{#1}%
   \expandafter\gdef\csname #1@numrows\endcsname{\qr@size}%
   \expandafter\gdef\csname #1@numcols\endcsname{\qr@size}%
   % we do not need to create blank because we store all
   \qr@placefinderpatterns{#1}%
   \qr@placetimingpatterns{#1}%
   \qr@placealignmentpatterns{#1}%
}

\newcount\c@fancy@a \newcount\c@fancy@b
% the normal data is... well...
\def\fancy@qr@writedata#1#2{%
  % #1 = name of a matrix that has been prepared with finder patterns, timing patterns, etc.
  % #2 = a string consisting of 0's and 1's to write into the matrix.
  \expandafter\c@fancy@a\the\numexpr\qr@numberofrowsinmatrix{#1}\relax
  \expandafter\c@fancy@b\the\numexpr\qr@numberofcolsinmatrix{#1}\relax
  \edef\qr@datatowrite{#2\relax}%
  \c@qr@i0\relax
  \@whilenum\c@qr@i<\c@fancy@a\do{%
      \c@qr@j0 \advance\c@qr@i\@ne
      \@whilenum\c@qr@j<\c@fancy@b\do{%
         \advance\c@qr@j\@ne
         \expandafter\fancy@qr@writebit\qr@datatowrite:{#1}%
      }%
  }%
}

\def\fancy@qr@writebit#1#2:#3{%
  % #3 = matrix name
  % (qr@i,qr@j) = position to write in (LaTeX counters)
  % #1 = bit to be written
  % #2 = remaining bits plus '\relax' as an end-of-file marker
  \edef\qr@datatowrite{#2}%
  \ifnum#1=1
    \qr@storetomatrix{#3}{\number\c@qr@i}{\number\c@qr@j}{\qr@black}%
  \else
    \qr@storetomatrix{#3}{\number\c@qr@i}{\number\c@qr@j}{\qr@white}%
  \fi
}%


\def\fancy@qr@printsavedbinarymatrix#1{%
   \def\qr@binarystring{#1\relax\relax}%
   \fancy@qr@setup{@tmp}%
   \fancy@qr@writedata{@tmp}{\qr@binarystring}%
   \fancy@qr@printmatrix{@tmp}%
}%

\newsavebox\fancyqr@imgbox
\define@key{fancyqr}{image x padding}{\def\fancyqr@img@padding@x{#1}}
\define@key{fancyqr}{image y padding}{\def\fancyqr@img@padding@y{#1}}
\define@key{fancyqr}{image padding}{\def\fancyqr@img@padding@x{#1}\def\fancyqr@img@padding@y{#1}}
\define@key{fancyqr}{image}{\@fancyqr@image@true\savebox\fancyqr@imgbox{#1}}
\define@key{fancyqr}{color}{\@fancyqr@gradientfalse\colorlet{qr@fancy@gradient@tl}{#1}}
\define@key{fancyqr}{left color}{\colorlet{qr@fancy@gradient@br}{#1}}
\define@key{fancyqr}{l color}{\colorlet{qr@fancy@gradient@br}{#1}}
\define@key{fancyqr}{right color}{\colorlet{qr@fancy@gradient@tl}{#1}}
\define@key{fancyqr}{r color}{\colorlet{qr@fancy@gradient@tl}{#1}}
\define@key{fancyqr}{gradient angle}{\def\fancyqr@gradient@angle{#1}}
\define@boolkey{fancyqr}[@fancyqr@]{gradient}[true]{}% if@fancyqr@gradient

\def\fancyqrset#1{\setkeys{qr,fancyqr}{#1}}
\fancyqrset{image padding=0,gradient=true,gradient angle=135,r color=teal,l color=purple}

\def\@fancyqr@init{\let\qr@printsavedbinarymatrix\fancy@qr@printsavedbinarymatrix\let\qr@matrixentry\fancy@qr@matrixentry\let\qr@printmatrix\fancy@qr@printmatrix}
\def\fancyqr{\@ifstar\s@fancyqr\ns@fancyqr}
% we rebuild some parts of qrcode to allow this macro to extend the keys while keeping the wrapper
\def\s@fancyqr{\qr@starinvokedtrue\@@fancyqr}
\def\ns@fancyqr{\qr@starinvokedfalse\@@fancyqr}
\newcommand\@@fancyqr[1][]{\begingroup\@fancyqr@init
\ifqr@starinvoked\qr@hyperlinkfalse\fi
\setkeys{qr,fancyqr}{#1}\bgroup
\qr@verbatimcatcodes\qr@setescapedspecials\qrcode@in}
\endinput

% TODO: NEGATIVE PATTERNS IF MIDDLE IS 0
% => make rounded negative corners